Certain current conventional vehicle wheel alignment systems use alignment elements referred to as “alignment heads” that are attached to the wheels of a vehicle to measure various angles of the wheels and suspension. These angles are communicated to a host system, where they are used in the calculation of vehicle alignment angles. In the standard conventional aligner configuration, four alignment heads are attached to respective wheels of a vehicle. Each alignment head comprises two horizontal or toe measurement sensors and two vertical or camber/ pitch sensors. Each alignment head also contains electronics to support overall sensor data acquisition as well as communications with the aligner console, local user input, and local display for status feedback, diagnostics and calibration support. Other conventional alignment systems, referred to as “visual aligners”, use optical targets attached to each vehicle wheel instead of sensors. The targets are imaged by cameras, and these visual images are used to calculate the vehicle wheel alignment angles.
Such alignment equipment usually includes a wheel clamp that attaches to a vehicle's wheel and carries the alignment element (i.e., the sensor equipment that measures the alignment angles of the vehicle, or the optical target). Referring now to FIG. 1, a conventional wheel clamp 100 includes a pair of upper and lower sliding brackets 105, 110, respectively, for engaging the rim of the vehicle wheel, and a center bracket 115 for holding an alignment element. Brackets 105, 110, 155 are all slidably mounted on a pair of guide bars 120, 125. A lead screw 130 threadingly engages upper and lower brackets 105, 110 for clamping the clamp 100 to the vehicle wheel. The vehicle being aligned is usually positioned on a vehicle alignment lift at heights from three to four feet for performing alignments. The vehicle is usually raised even higher, up to six feet, for servicing the vehicle from underneath.
There exist a need to lower the weight of alignment equipment, such as wheel clamp 100, that an alignment technician attaches to a vehicle's wheel. Lower weight reduces the amount of kinetic energy (i.e., shock loading) that is imparted to this equipment in case it falls off a wheel to which it is attached, thereby reducing the chance of damaging the equipment. Lower weight has the added benefit of reducing strain and fatigue on the technician lifting and holding this equipment up until it can be attached to a vehicle's wheel. A typical four-wheel alignment requires the technician perform such a lifting/holding operation for each of the four wheels of the vehicle, and this operation may be performed several times a day in a typical alignment shop.